Automatic pressure release ratchet wrench



Nov. 14, 139. c. A. LATIMER 2.179.855

AUTOMATIC PRESSURE RELEASE RATCHET WRENCH Filed May 25, 1938 2 Sheets-Sheet 1 Flci FIGZ INVENTOR ATTORNEY 'FIG?) Nov. 14, 1939. c. A. LATIMER 2.179.855

AUTOMATIC fRESSURE RELEASE RATCHET WRENCH Filed May 25, 1958 2 Sheets-Sheet 2 I'IH INVENTOR ATTORNEY atenteol Nov. 14, 1939 iTE AUTOMATIC PRESSURE RELEASE RATCHET. WRENCH Charles A. Latimer, Toledo, Ohio Application May 25, 1938, Serial No; 210,017

Claims.

' of the different structures that contain the invention and shall describe the selected wrench' hereinafter. The particular structure selected is shown in the accompanying drawings.

Fig. l is a side view of the wrench. Fig. 2 is a View of a longitudinal section of a part of the wrench taken on the plane of the line 22 indicated in Fig. 1. Fig. 3 is a view of a section of a part of the wrench taken on the plane of the line 3-4.2 indicated in Fig. 2. Fig. 4 illusthe elements of the wrench are shown in one relation to each other. Fig. 5 illustrates a view similar to that shown in Fig. 4, but showing the said elements in another relation to each other.

The wrench l is provided with a handle 2 located on one end of a bifurcated shank l, which may be formed of two strips of metal suitably shaped and secured to a threaded block 5 by means of the rivets l. The handle is interiorly tapped and may be adjustably located along the block by rotation of the handle. The position of the handle, with reference to the bifurcated shank, may be indicated by the ends of a sheet metal strip 33 bent U-shape, and slidably movable along the shank as the handle is moved longitudinally with respect to the shank. The U-shaped strip 8 may be secured by means of a stud or set screw It! located in the end of the handle 2. One end of the screw it is provided with a neck 45 and head ii. The neck extends through the strip 3 and the head ll connects the screw ii! to the strip and permits rotation of the screw relative to the strip to adjust the strip relative to the shank and permit rotation of the handle and screw relative to the strip. The opposite sides of the shank d are provided with indicators i2 comprising a plurality of spaced markings formed on the outer sides of the shank d in the 5; vicinity of the ends of the strip. The location of trates a part of the wrench wherein certain of 1 the ends of the strip will, thus, indicate the relative location of the handle on the shank.

The bifurcated end parts M of the shank 4 are enlarged and, preferably, are formed circular in outline. The end parts are provided with large 5 circular openings 15-. A toothed ratchet wheel ll is located intermediate the end parts l4 and is provided with hubs l8 which project into and fit the openings I5, but with suitable clearance to enable rotation of the ratchet wheel ll relative to the shank 4. Preferably, the center of rotation of theratchet wheel is located in a line disposed parallel to and spaced from the longitudinal axis of the shank.

A dog 2G is located intermediate the bifurcations of the shank 4 and is pivotally connected thereto by means of a pin 2! located in short slots 22 formed in the, sides of the shank. The pin 2! is, preferably, disposed between end parts of the U-shaped strip 6 to retain the pin within the slots 22. A suitable flanged collar 24 and a spring 25 are located on the shank. The spring is disposed intermediate the collar 2d and one end of the handle 2. The dog is provided with shoulders 2'! that protrude from the 25 side edges of the shank and are engaged by the collar 24. The collar and the engaging surfaces of the shoulders are located in a plane extending transverse the shank and, preferably, through the axis of the pivot pin 2i. The shoulders 2i have rounded corners 2G to produce a rocking movement of the dogon the collar when the dog is tilted relative to the shank. The spring 25 operates to press the collar against the shoulders and press the pin it to the ends of the slots 22, remote from the handle with a pressure that is dependent upon the relative location of the handie on the shank. The indicator 25 thus indicates the pressure of the spring 25. The markings i2 may be suitably positioned relative to each other, by calibration, to indicate pounds pressure, or the markings may be marked with suitable indicia to indicate desired pressures to which the ele ments arev to be subjected by the operation of the wrench. The spring operates to normally maintain the dog 26in position to engage the toothed ratchet Wheel 11. Deflection or" the dog, by tilting, from its normal engaging relation upon return rotation of the handle as the dog is drawn over the teeth, is resiliently resisted by the pressure of the spring Zion one of the shoulders 21!.

The end edge 38 of the dog is inclined to its longitudinal axis which extends at right angles to the plane of thesurfac-es of the shoulders 21.

The side edge 29 of the dog 20 is parallel to its longitudinal axis. A roller 32 is disposed on a bolt 34 and intermediate the bifurcations of the shank 4 and, normally, in contact with the side edge 29 to limit rotative movements of the dog in one direction. The upper ends of the slots 22 also limit the reciprocatory movements of the dog in one direction.

The teeth 28 of the ratchet are V-shaped and the corner formed between the end edge 30 and the side edge 29 of the dog, engages in the valley or the corner formed between the contiguous surfaces of two of the teeth. The center of the ratchet is located with reference to the side edge 29 such that the line of the side edge crosses a radius of the ratchet at right angles and near a central point of the said radius. Also, the relative inclination of the surfaces of the teeth to the radii through their points or centers, and the inclination of the end edge 30 to the side edge 29 of the dog, are such as to dispose the following surface of the leading of the said two teeth, with respect to the direction in which the ratchet is rotated by the wrench, coincident with the surface of the end edge 30. Thus, upon aratchetdriving movement of the handle, the pressure of the spring is transmitted to the tooth engaged by the dog, and if movement of the ratchet is resisted, the point of the said tooth engages the end edge 30 of the dog to press the dog 20 counter to the pressure of the spring 25.

The toothed ratchet wheel I! is provided with a suitable opening 3 l such as a hex or a square, for receiving an element, such as a nut, bolt head, or a connector for connecting an element to the wrench, which is to be operated by the wrench. When the wrench is connected to an element, such as a nut or other threaded element, for rotating the element clockwise about'the axis of the element, the tool is located in the position shown in Fig. 1, and the handle is moved clockwise, which causesthe dog to engage the ratchet and rotate the element, and if there is some resistance to return rotation of the element, the end of the dog 20 will move over the teeth, as indicated in Fig. 5, when the wrench handle is moved counter-clockwise. Upon succeeding movements of the handle to the left, the dog 20 will engage the ratchet and rotate the element step by step.

When it is desired to rotate the element until it meets a definite predetermined resistancathe spring 25 is adjusted accordingly, as may be indicated by the position of the strip 8 relative to the indicator l2. When the predetermined resistance to the pressure of the element, produced by its rotation, is reached, the end edge 30 of the dog will tilt on the point of the tooth engaged by the dog, as shown in Fig. 4. As the handle is further moved in its rotation clockwise, the end edge 30 will slide along the point of the tooth depressing the dog counter to the pressure of the spring 25, and the pivot pin will move along the slots 22 by reason of the movement of the side edge 29 of the dog toward an alignment with radius extending through the point of the tooth. The maximum pressure of the spring to produce rotation of the ratchet occurs during the initial angular movement of the end edge relative to the tooth engaged, since, at that point, the pressure of the spring is exerted atright angles to one. of the radii and, as the handle moves, the line of the pressure of the spring extends through the point of the tooth and the line approaches the dead center of the ratchet togglewise, which increases the mechanical advantage of the spring. This produces a definite pressure point in the resistance of the element to rotation that releases the element from the wrench and prevents an increased operating pressure due to friction of parts of the wrench, or otherwise. When the end edge 30 of the dog slips by the tooth, further rotation of the element will be prevented.

I claim:

1. In an automatic pressure-release wrench, a toothed ratchet wheel, means for connecting the ratchet to a rotatable element, a shank for rotatably supporting the ratchet, a dog for engaging the teeth of the ratchet, the shank having a slot, a pivot pin located in the slot for pivotally supporting the dog, a spring for yieldingly pressing the dog along the slot and to one end of the slot and resisting pivotal movements of the dog about the said pin, and means located on the shank for preventing tilting movements and longitudinal movements each in one direction.

2. In an automatic pressure-release wrench, a toothed ratchet wheel, means for connecting the ratchet to a rotatable element, a dog for engaging the ratchet teeth, a pivot pin for pivotally supporting the dog, a spring exerting its maximum producible pressure in a direction endwise of the dog, the dog having a shoulder operable against the pressure of the spring when the dog is tilted on the pin in one direction and moves over the points of the teeth of the ratchet by movement of the wrench in one direction, a guide for preventing tilting of the dog on the pin in a direction opposite to the said one direction and directing movement of the dog endwise when engaging a tooth of the ratchet, and the Wrench is rotated in the said one direction.

3. In an automatic pressure-release wrench, a toothed ratchet wheel, means for connecting the ratchet to a rotatable element, a shank for rotatably supporting the ratchet, a dog for engaging the teeth of the ratchet, the dog having a side edge, the side edge of the dog being located substantially parallel to the longitudinal axis of the shank and an end edge inclined to the side edge,

. the shank having a slot, a pivot pin located in the slot for pivotally supporting the dog, a spring for pressing the dog in a direction of the longitudinal axis of the shank and the pivot pin against one end of the slot, the dog having a part engaged by the spring and located at one side of the pivot pin with reference to the longitudinal axis of the shank for yieldingly resisting tilting movements of the dog in one direction, means located on the shank for engaging the said side edge of the dog and for preventing tilting movements in a direction opposite to the said one direction, and the teeth of the ratchet operable to tilt the dog when the shank is rotated in one direction and for engaging the dog for resisting movement of the wrench by pressure exerted in the direction of the longitudinal axis of the shank.

4. In an automatic pressure-release wrench, a shank, a tooth-ed ratchet wheel rotatably supported on the shank, means for connecting the ratchet to a rotatable element, a dog having a longitudinal axis substantially parallel to the longitudinal axis of the shank, a pivot pin for pivotally supporting the dog, the shank having a slot for receiving the pivot pin, a spring surrounding the shank for engagement of one end of the dog to press the pivoted end of the dog along the slot, the dog having means for engaging the spring to yieldingly resist pivotal movements of the dog in one direction, the shank having means for preventing pivotal movements of the dog in a direction opposite to the said one direction, and the teeth of the ratchet operating to move the pivot pin along the slot against the pressure of the spring When the element is rotated by the Wrench.

5. In an automatic pressure-release Wrench, a shank, a toothed ratchet Wheel rotatably supported on the shank, means for connecting the ratchet to a rotatable element, a dog having a longitudinal axis substantially parallel to the iongitudinal axis of the shank, a pivot pin for pivotally supporting the dog, the shank having a slot for receiving the pivot pin, a spring surrounding the shank for engagement of one end of the dog to press the pivoted end of the dog along the slot, the dog having means for engaging the spring to yieldingly resist pivotal movements of the dog in one direction, the shank having means for preventing pivotal movements of the dog in a direction opposite to the said one direction, the dog having an end edge and a side edge, and the center of the ratchet being disposed With reference to the shank to normally locate the following side surfaces of succeeding teeth in the plane of the end edge surface of the dog to produce tilting movements of the surface of the end. edge of the dog relative to the point of the tooth engaged by the dog counter to the pressure of the spring upon rotation of the shank relative to the ratchet in one direction.

CHARLES A. LATIMER. 

